PHP: How to get keyless URL parameters - php

Question

I would like to get the parameter in a key such as http://link.com/?parameter
I read somewhere that the key is NULL and the value would be parameter.
I tried $_GET[NULL] but it didn't seem to work.
Here is my code:
if ($_GET[NULL] == "parameter") {
echo 'Invoked parameter.';
} else {
echo '..';
}
It just prints out .. so that means I'm not doing it right. Can someone please show me the right way.

Answer 1

There are no such things as keyless URL parameters in PHP. ?parameter is the equivalent of $_GET['parameter'] being set to an empty string.
Try doing var_dump($_GET) with a url like http://link.com/?parameter and see what you get.
It should look something like this:
array (size=1)
'parameter' => string '' (length=0)
Thus, you can test it in a couple of ways depending on your application needs:
if (isset($_GET['parameter'])) {
// do something
} else {
// do something else
}
or
// Only recommended if you're 100% sure that 'parameter' will always be in the URL.
// Otherwise this will throw an undefined index error. isset() is a more reliable test.
if ($_GET['parameter'] === '') {
// do something
} else {
// do something else
}

Answer 2

$_GET is a super global assoc array, that contains parameter=>it's value pairs. So, parameter is a key of the array.
For example, if your url is something like this: myweb.com/?page=load&do=magic than you $_GET is:
$_GET(
[page] => load
[do] => magic
)
If you want just to test, if parameter is in you URL as a param, you should do something like this:
if (isset($_GET['parameter'])
echo "Here I am!";

Answer 3

You can also get the entire request_url like this
echo $_SERVER['REQUEST_URI'];
To get the part after ?:
echo explode('?', $_SERVER['REQUEST_URI'])[1];

Answer 4

You can get the part of the URL beginning with ? with
$_SERVER['QUERY_STRING']

Answer 5

You could via array_keys():
$param = array_keys($_GET)[0];
Which would give you the name of the first querystring parameter, whether it has a value or not.
You could also get all of the parameters without a value like so:
$empty = [];
foreach($_GET as $key => $value)
if(strlen($value) === 0) $empty[] = $key;
print_r($empty);